moment of inertia
9.Based on the same principle of floating stability calculation of rectangle caisson, the moment of inertia of gravity axis of the fan shape is transformed through coordinate transformation formula, and the general formula and calculation method of floating stability for c limier caisson with partition ails are obtained.
10.Theorem of kinetic energy is the basic universal method to calculate the fly wheel and the correspondent moment of inertia of loading move which converts into a axle, four big mechanisms of lift are presented in the paper, for lifting, travelling and rotating mechanism, the calculating, is much simpler than before of the equivalent method for calculating moment of inertia.

